MySQL Slow Queries Log: Lock_time

In MySQL's slow queries log, it'll have an entry like this:

# User@Host: scc_service[scc_service] @  [192.168.249.209]
# Query_time: 43  Lock_time: 0  Rows_sent: 0  Rows_examined: 0
SET timestamp=1237769209;
UPDATE loan SET funding_status="scheduled",datetime_approved=now() WHERE loan_id = '00000';

What does Lock_time refer to? Is that how long the query spent waiting for a lock, or how long this query locked the database?

Lock_time indicates the time spent waiting for a lock, due to another query holding a lock

Fantastic, thanks.